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[几何] 立几小题

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青青子衿 Posted at 2014-1-23 15:30:42 |Read mode
空间四边形ABCD中AB⊥CD,BC⊥AD,下列哪些命题是假命题:
①AB⊥平面BCD;②BC⊥平面BAD;③平面BAD⊥平面BCD;④AB⊥BD;⑤AD⊥CD

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其妙 Posted at 2014-1-23 17:00:35
回复 1# 青青子衿
对棱互垂?
正四面体就满足,你说那些是假命题呢?

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 Author| 青青子衿 Posted at 2014-1-23 18:30:31
回复 2# 其妙
对棱互垂?
正四面体就满足,你说那些是假命题呢?

对棱互垂怎么推出正四面体?? 谢谢!

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2025-4-22 12:59 GMT+8

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